Borthwick-Jackson’s first professional contract is due to expire in the summer and is set to be replaced by the new agreement, which will be worth £2.5million.

Varela, who was blocked by Van Gaal from a deadline-day loan move to Genoa, is also in talks about a deal to replace his current agreement, which expires in 2018.

Left-back Borthwick-Jackson, 19, has made nine appearances for United since breaking into the first team in November and has impressed after getting his chance following a series of serious injuries sustained by the club’s senior full-backs.

Fast lane: Borthwick-Jackson is making quick strides in his Manchester United career

Varela, 22, played the full 90 minutes of last Friday’s 3-1 FA Cup fourth-round win over Derby after stepping in for the injured Matteo Darmian.

But Darmian was restored to the starting line-up at right-back in Tuesday’s 3-0 win over Stoke, with Varela an unused substitute.

The Premier League club have been beset by a series of injuries to their full-backs, with Luke Shaw, Antonio Valencia, Marcos Rojo, Phil Jones and Ashley Young all long-term absentees.

Uruguayan Varela, who is principally a right-back, was the first signing made by former manager David Moyes and spent last season on loan at Real Madrid’s B team Castilla.